If you don't need the tall top gear, you can go even smaller , 48, a 6t difference.

suppose with a strong tailwind, the 48-14 may not be big enough..

Thats just an opinion..

Toured with a load for months with no higher than a 50/14 and it was fine.

freewheels as 7 speeds or 6 are 13t at the smallest,
Freewheel hub, Phil, is what I used..